1. Field of the Invention
This invention relates generally to blood control systems for use by surgeons and more particularly is directed towards a new and improved cardiotomy suction circuit.
2. Description of the Prior Art
In many surgical procedures and particularly in open heart surgery, a serious problem has existed in controlling the rate at which blood is sucked from the area in and around that portion of the patient being operated upon. In practice, a relatively large pool of blood will form in a body cavity and this blood normally is returned to the patient through auto-transfusion, after first being oxygenated. Systems presently available for collecting blood in this manner are commonly referred to as cardiotomy suction circuits, and those currently in use involve direct suction lines, with the suction rate being controlled by various techniques such as foot pedals, finger-operated open ports on the suction line, remote control switches for pumps and other means. None of the systems heretofore available has been entirely satisfactory for various reasons. For example, the foot operated pedals may be accidentally displaced by members of the operating team kicking the pedal, which is then hard to find under the operating table. The use of an open port on a direct blood suction line subjects the blood to continuous negative pressure as well as exposing the blood to the rushing, incoming air. The continuous negative pressure applied to the blood is harmful to the blood cells and the frothing action produced in the blood by the continuous air flow in the blood is a major source of hemolysis. Also, any bacterial contamination of the operating room air may produce direct inoculation into the patient's blood since more than 2000 liters of room air may be bubbled into the patient's blood during a typical two hour pump run. Other systems have been developed but also have been found unsatisfactory from the standpoint of efficiency, simplicity, control and blood protection.
Accordingly, it is an object of the present invention to provide a new and improved cardiotomy suction control system. Another object of this invention is to provide a vernier suction control system for use in surgical operations whereby blood collected by a suction system is transferred in a substantially closed system without being exposed to continuous negative pressure or to ambient air.